Dissolved and Suspended Polycyclic Aromatic Hydrocarbons (PAH) in the North Aegean Sea

The distribution and sources of polycyclic aromatic hydrocarbons (PAH) were investigated in the seawater of the North Aegean Sea. The measured PAH concentrations in SPM are generally considered as elevated for open sea waters and were evenly distributed in the area. Their levels in the dissolved phase (1.6-33.0 ng/l) were much higher than those encountered in the corresponding particulate phases (0.04-10.2 ng/l). The PAH patterns in both phases were dominated by the three ring aromatics and their alkylated derivatives, reflecting a predominant contribution of fossil hydrocarbons probably related to ship traffic, whereas no significant inputs from the rivers outfalling in the area were detected. In bottom waters PAH values were generally lower, whereas a higher depletion of the petroleum PAH in comparison with the pyrolytic ones according to depth was observed

Hydrology and pollution assessment in a coastal estuarine system. The case of the Strymonikos Gulf (North Aegean Sea)

Three hydrographic cruises were undertaken to study the hydrology and to estimate the ecological status of the coastal ecosystem of the Strymonikos Gulf (North Aegean Sea) impacted by the riverine waters of the Strymon River. Surface sediments were also collected in order to determine the levels of organic contaminants in the gulf. Three main water masses were identified in the Strymonikos Gulf throughout the year: a) the surface river plume water, b) the surface and subsurface Black Sea Water and c) the near bottom (>50 m) water of Levantine origin. High nutrient concentrations were recorded close to the mouth of the river, indicating a rather eutrophic environment, which was restricted near the river discharge. The salinity-nutrient correlations of the surface waters of the study area were linear, indicating that the riverine waters are the major source of nutrient in the gulf. DIN:P ratios varied seasonally from relatively higher values during winter and early spring to lower values in late spring-early summer. This led to a shift from likelihood P-limitation during winter and early spring to N-limitation in late spring – early summer. Total hydrocarbon concentrations measured in the sediments ranged from 19.2 to 95.9 μ g/g, whereas total polycyclic aromatic hydrocarbon (PAH) values varied between 107.2 and 1019 ng/g. The application of different diagnostic criteria suggests a natural terrestrial origin for aliphatic hydrocarbons and pyrolytic origin for the PAHs. DDTs displayed the highest concentrations of all the organochlorines determined, whereas polychlorinated biphenyl (PCBs) concentrations were very low. Riverine input seems to be the major source for all the compounds identified

Plant condensates: no longer membrane-less?

Cellular condensation is a reinvigorated area of study in biology, with scientific discussions focusing mainly on the forces that drive condensate formation, properties, and functions. Usually, condensates are called 'membrane-less' to highlight the absence of a surrounding membrane and the lack of associated contacts. In this opinion article we take a different direction, focusing on condensates that may be interfacing with membranes and their possible functions. We also highlight changes in condensate material properties brought about by condensate-membrane interactions, proposing how condensates-membrane interfaces could potentially affect interorganellar communication, development, and growth, but also adaptation in an evolutionary context. We would thus like to stimulate research in this area, which is much less understood in plants com-pared with the animal field

Concentrating and sequestering biomolecules in condensates: impact on plant biology

Biomolecules can exist in a variety of forms, ranging from single entities to mesoscale assemblies akin to small organelles, also known as ‘biomolecular condensates’. The formation of biomolecular condensates is expedited by phase separation, in which molecules de-mix to form dilute and condensed phases. Phase separation results in concentrating or sequestering certain molecules, thus altering their abundance or other features in the phases and in this way inhibiting or promoting biochemical reactions. Here, we discuss recent research implicating biomolecular condensates in the regulation of biochemical reactions in plants

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas : the PERSEUS experience

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES. 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license.peer-reviewe

Marine chemical contaminants – support to the harmonization of MSFD D8 methodological standards: Matrices and threshold values/reference levels for relevant substances

According to the Article 17(2) of the Marine Strategy Framework Directive (MSFD), Member States have to review and update their marine strategies every six years. This requires updates of the MSFD Articles 8, 9 and 10 by 2018. The current report provides an overview of the substances, matrices and threshold values that Member States intend to use for the assessment of the Descriptor 8 in this MSFD reporting cycle. This compilation aims at evaluating gaps and discrepancies between Member States and identifying aspects that need further harmonization. It also helps understand which issues should be addressed to achieve consistency with the new MSFD Commission Decision (EU 2017/848). The information has been gathered from the contributions of the MSFD Expert Network on Contaminants, an informal network established to support MSFD implementation. This work is part of a process to help regulators to assess relevant contaminants in their jurisdictional area, thus aiming at EU national authorities but also at Regional Sea Conventions in the shared marine basins.JRC.D.2-Water and Marine Resource

Surface sediment chemistry in the Olympic Games 2004 Sailing Center (Saronikos Gulf)

Construction of the Olympic Games 2004 Sailing Center is planned in the Saronikos Gulf, in the area of Agios Kosmas. A multi-disciplinary base-line study was carried out to provide background levels of inorganic and organic pollutants before the construction. Two shallow reefs (water depth 2-3 m) are the predominant features in the area’s underwater topography. The reef consists of solid rock formations and pebbles, whereas sandy sediments cover predominantly the remaining seabed. Some pockets of fine-grained sand were identified within the existing marina. Sedimentary heavy metal contents were found to be low, showing only slight heavy metal enrichment, attributed mainly to heavy mineral abundance in the area. A small enrichment for lead could be related to anthropogenic sources. Patterns of low concentrations were observed for organic carbon and organic nitrogen. Conversely, the sediment petroleum hydrocarbon content was found to be relatively high, implying anthropogenic pollution related to ship effluents and increased marine traffic

Polycyclic aromatic hydrocarbons (PAHs) in marine sediments of the Hellenic coastal zone, eastern Mediterranean: Levels, sources and toxicological significance

Purpose: Polycyclic aromatic hydrocarbons (PAHs) are widespread in sediments, particularly near areas of intense human activities. Due to their mutagenic and carcinogenic behaviour, PAHs are classified as priority contaminants to be monitored in environmental quality control schemes. The purpose of this study was to determine the levels of PAHs in major coastal areas of Greece that receive various pressures, investigate their sources and evaluate their potential toxicity by comparison against effects-based Sediment Quality Guidelines (SQG). Materials and methods: Forty-one sediment samples were collected from four areas of the Hellenic coastline. PAH concentrations were determined by GC-MS, after Soxhlet extraction and fractionation by silica column chromatography. Source apportionment was conducted by isomeric ratio diagnostic criteria. The mean quotient Effects Range-Median (m-ERM) was used to evaluate the potential of adverse effects posed to benthic organisms. Results and discussion: The levels of PAHs were found to vary widely from 100 to more than 26,000 ng g-1. The highest levels were found in the close vicinity of an alumina production plant in the Gulf of Corinth. High levels of PAHs were also found at a few sites in each of the areas studied, close to a nickel production plant (North Evoikos Gulf), at the rainwater and wastewater outfalls of the great urban areas of Athens and Thessaloniki and at the industrialized area of Elefsis Bay (Saronikos Gulf). At the most contaminated sites PAH had a pyrolytic origin. Comparison of PAH levels to the SQG indicated that less than 15% of the sites studied have an intermediate probability (24-49%) of being toxic. Conclusions: In general, discrete point sources were identified as the major contributors of PAH contamination in the Hellenic coastal zone. Therefore, source control measures should be considered for protecting, or restoring, sediment quality, particularly in areas that support a diversity of anthropogenic activities (e. g. fishing, tourism, industry). © 2011 Springer-Verlag

Dissolved and particulate trace metals in a wetland of international importance: Lake Mikri Prespa, Greece

This paper reports the dissolved and particulate trace metal distributions in Lake Mikri Prespa, wetland of NW Greece. The concentrations of Cu, Pb, Zn, Cd, Al, Fe, Mn, Ni and Cr were determined in surface and hypolimnetic waters as well as in the inputs and the outflow. Trace metals were connected with two major populations of suspended particles, identified by using the recovery ratio for two different leaching reagents, namely 0.5 N HCl and 1:1 hot aqueous HNO3. The first group is land derived entering the lake through runoff and plays a rather restricted role in its geochemistry. The second group which is more important includes authigenic carbonates, Fe and Mn hydroxides and oxides and organic rich particulates. © 1989 Kluwer Academic Publishers